Snowkitepro and Ozonerider Sigve Botnen resently nearly nailed the first ever backside 720 on snow. (spring 2009) This might have been the first bs 7 water and snow? Last year Petter Johnsen stomped the first frontside 720 in the movie Dimensions.
On a kicker in the hills of the Hardangervidda, Sigve manned himself up in the light breeze. Took off the leach and just went for it.
"Nailing" might be a hard statement, since Sigve did a roll after the landing, that was not quite steep enough in the rotten spring snow.